Radar systems having rotary antenna arrays are used in aircraft surveillance systems, on board ships and on land mounted radar installations. The elements of the antenna array must be individually fed from an RF transmission line. Rotary couplers are employed to transfer or transmit RF energy from the mixed equipment to the antenna elements. In general, the antenna arrays require rotary couplers capable of providing RF energy to, and receiving RF energy from, the multiple antenna elements through separate transmission lines. In the past, coaxial rotary couplers for multiple transmission lines have been large and cumbersome. There is a need for a compact coaxial rotary coupler.